Lava flows are typically finer grained than intrusive igneous rocks. Why?
The extrusive magma cools quickly so the mineral grains do not have time to grow.
The sizes, shapes, and arrangements of mineral grains in an igneous rock is known as ________.
________ mineral grains are of roughly equal size and coarse enough to be seen without a microscope or magnifying glass.
A ________ is an open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid.
Consider the Bowen's reaction series. Which mineral would you expect to see as a phenocryst in a porphyritic basalt?
Which of the following best describes an aphanitic texture?
The rock is crystalline; mineral grains are too small to be visible without a magnifying lens or microscope.